Question

Rziwąż układy równań:

a) {x-y=2

x+y=2

b) {x+2y=1

2x-y=-3

c) {5x-y=2

x+3y=-4

Answer 1

x - y = 2

x + y = 2

x +x-y+y = 2+2

2x =4

x=2

 

 

x+2y=1 / *(-2)

2x-y=-3

-2x+2x-4y-y=-2-3

-5y=-5

y=5

 

 

 

5x-y=2  /*3

x+3y=-4

15x+x-3y+3y=6-4

16y=2

y=1/8

Answer 2

x-y = 2

x+y = 2  

---------

2x=4 / :2

x=2

 

2 - y=2

-y=2-2

y=0

 

x+2y=1 / x(-2)

2x-y=3

 

 

-2x-4y=-2

2x-y=3

-------

 

-5y=1

y=-1/5

 

2x+1/5=3

2x =3-1/5

2x= 14/5  /:2

x= 14/5 x 1/2

x=7/5

 

 

5x-y=2

x+3y=-4 /x(-5)

 

 

 

5x-y=2

-5x-15y=20

-----------

 

-16y=22 / : (-16)

 

y=- 22/16 = -11/8

 

5x +11/8 =2

5x=2-11/8

5x=5/8   /:5

x= 5/8 x 1/5

x=1/8